Immune cell interactions are critical in HIV pathogenesis. These interactions involves in antigen presentation between antigen presenting cells and T/B lymphocytes, capturing and transmission of virus from monocyte and dendritic cells to resting T cells, and depletion of CD4 cells through cell membrane receptors of apoptosis pathways. The study in my laboratory will focus on the determination of the critical molecules on immune cells involved in HIV transmission and depletion of CD4 T cells, and the regulation of the gene expression of these molecules by viral components. The experiment will be performed both in vitro using cell culture system and in vivo using human/SCID reconstitution system. The pathogenesis of HIV-1/2 subtypes in induction of T cell apoptosis will be studied. The cytokine and chemokine productions will be also analyzed.